scholarly journals Laboratory Experimental Setup and Research on Heat Transfer Characteristics during Secondary Cooling in Continuous Casting

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 61 ◽  
Author(s):  
Yazhu Zhang ◽  
Zhi Wen ◽  
Zengwu Zhao ◽  
Chunbao Bi ◽  
Yaxiang Guo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Continuous Casting ◽  
Water Flux ◽  
Spray Cooling ◽  
Heat Fluxes ◽  
Secondary Cooling ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Surface Temperatures

Spray cooling is a key technology in the continuous casting process and has a marked influence on the product quality. In order to obtain the heat transfer characteristics, which are closer to the actual continuous casting to serve the design, prediction and simulation, we created an experimental laboratory setup to investigate heat transfer characteristics of air mist spray cooling during the continuous casting secondary cooling process. A 200-mm thick sample of carbon steel was heated above 1000 °C, and then cooled in a water flux range of 0.84 to 3.0 L/(m2∙s). Determination of the boundary conditions involved experimental work comprising an evaluation of the thermal history and the heat flux and heat transfer coefficient (HTC) at the casting surface using inverse heat conduction numerical schemes. The results show that the heat fluxes were characterized via boiling curves that were functions of the slab surface temperatures. The heat flux was determined to be 2.9 × 105 W/m2 in the range of 1100 to 800 °C with a water flux of 2.1 L/(m2∙s). The critical heat flux increased with the increase of water flux. The HTC was close to a linear function of water flux. We also obtained the relation between the HTC and the water flux in the transition boiling region for surface temperatures of 850 to 950 °C.

Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point

2019 ◽  
Author(s):  
Ganesh Guggilla ◽  
Arvind Pattamatta ◽  
Ramesh Narayanaswamy
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Heated Surface ◽  
Electronics Cooling ◽  
Spray Cooling ◽  
High Heat ◽  
Heat Fluxes ◽  
Air Cooling ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract Due to the advancements in computing services such as machine learning and artificial intelligence, high-performance computing systems are needed. Consequently, the increase in electron chip density results in high heat fluxes and required sufficient thermal management to maintain the servers. In recent times, the liquid cooling techniques become prominent over air cooling as it has significant advantages. Spray cooling is one such efficient cooling process which can be implemented in electronics cooling. To enhance the knowledge of the process, detailed studies of fundamental mechanisms involved in spray cooling such as single droplet and multiple droplet interactions are required. The present work focuses on the study of a train of droplets impinging over a heated surface using FC-72 liquid. The surface temperature is chosen as a parameter, and the Dynamic Leidenfrost point (DLP) for the present impact conditions is identified. Spread hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.

Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point

2021 ◽  
Author(s):  
Ganesh Guggilla ◽  
Ramesh Narayanaswamy ◽  
Peter Stephan ◽  
Arvind Pattamatta
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Heated Surface ◽  
Contact Angle Hysteresis ◽  
Electronics Cooling ◽  
Spray Cooling ◽  
Heat Fluxes ◽  
High Speed Photography ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract High-performance computing systems are needed in advanced computing services such as machine learning and artificial intelligence. Consequently, the increase in electron chip density results in high heat fluxes and requires good thermal management to maintain the servers. Spray cooling using liquid offers higher heat transfer rates and is efficient when implemented in electronics cooling. Detailed studies of fundamental mechanisms involved in spray cooling, such as single droplet and multiple droplet interactions, are required to enhance the process's knowledge. The present work focuses on studying a train of two FC-72 droplets impinging over a heated surface. Experimental investigation using high-speed photography and infrared thermography is conducted. Simultaneously, numerical simulations using opensource CFD package, OpenFOAM are carried out, emphasizing the significance of contact angle hysteresis. The surface temperature is chosen as a parameter, and different boiling regimes along with Dynamic Leidenfrost point (DLP) for the present impact conditions are identified. Spreading hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.

Heat Transfer Characteristics of Downward Facing Hot Horizontal Surfaces Using Mist Jet Impingement

2017 ◽  
Author(s):  
Ashutosh Kumar Yadav ◽  
Parantak Sharma ◽  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Vishal Nirgude ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Cooling System ◽  
Water Pressure ◽  
Jet Impingement ◽  
Surface Heat ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Impinging jet cooling technique has been widely used extensively in various industrial processes, namely, cooling and drying of films and papers, processing of metals and glasses, cooling of gas turbine blades and most recently cooling of various components of electronic devices. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. Controlled cooling, as an important procedure of thermal-mechanical control processing technology, is helpful to improve the microstructure and mechanical properties of steel. In industries for heat transfer efficiency and homogeneous cooling performance which usually requires a jet impingement with improved heat transfer capacity and controllability. It provides better cooling in comparison to air. Rapid quenching by water jet, sometimes, may lead to formation of cracks and poor ductility to the quenched surface. Spray and mist jet impingement offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronics industries. Mist jet impingement cooling of downward facing hot surface has not been extensively studied in the literature. The present experimental study analyzes the heat transfer characteristics a 0.15mm thick hot horizontal stainless steel (SS-304) foil using Internal mixing full cone (spray angle 20 deg) mist nozzle from the bottom side. Experiments have been performed for the varied range of water pressure (0.7–4.0 bar) and air pressure (0.4–5.8 bar). The effect of water and air inlet pressures, on the surface heat flux has been examined in this study. The maximum surface heat flux is achieved at stagnation point and is not affected by the change in nozzle to plate distance, Air and Water flow rates.

Sign in / Sign up

Export Citation Format

Share Document